Search for a narrow resonance lighter than 200 GeV decaying to a pair of muons in proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports a search for narrow resonances decaying into muon pairs in proton-proton collisions at 13 TeV, covering masses below 200 GeV, and sets new constraints on dark photon models.

Contribution

It introduces a combined analysis using conventional and high-rate triggers to search for low-mass muon resonances at the LHC, improving existing constraints.

Findings

No significant resonance signals observed.

Sets the most stringent limits on dark photons in 30-75 and 110-200 GeV ranges.

Analyzed data with integrated luminosities of 137 fb$^{-1}$ and 96.6 fb$^{-1}$.

Abstract

A search is presented for a narrow resonance decaying to a pair of oppositely charged muons using $\sqrt{s} =$ 13 TeV proton-proton collision data recorded at the LHC. In the 45-75 and 110-200 GeV resonance mass ranges, the search is based on conventional triggering and event reconstruction techniques. In the 11.5-45 GeV mass range, the search uses data collected with dimuon triggers with low transverse momentum thresholds, recorded at high rate by storing a reduced amount of trigger-level information. The data correspond to integrated luminosities of 137 fb$^{-1}$ and 96.6 fb$^{-1}$ for conventional and high-rate triggering, respectively. No significant resonant peaks are observed in the probed mass ranges. The search sets the most stringent constraints to date on a dark photon in the $\sim$30-75 and 110-200 GeV mass ranges.